Doctors could boycott a Tory town hall’s plans to dock benefits from overweight people who refuse to get fitter, a senior MP said today.

Westminster council is considering the deeply controversial scheme as local authorities take on public health responsibilities in April.

Overweight benefit claimants could lose housing and council tax benefit if they do not follow exercise regimes prescribed by doctors.

Oyster-style smart cards could be brought in to monitor the use of leisure centres.

Conservative MP Stephen Dorrell, chairman of the Commons health committee, backed moves to get people to take more responsibility to not have to rely on the State.

But he warned that doctors could refuse to take part in the scheme if it was seen as penalising people for being unhealthy or unfit – rather than for not taking action to deal with their condition and so become less dependent on the state.

“I think doctors will certainly be concerned about that boundary,” he added.

Several councils have already introduced schemes that allow doctors to prescribe exercise at local facilities including swimming pools, gyms, yoga and walking clubs.

A spokesman for Westminster said the Conservative-run council would operate a carrot and stick approach and offer financial rewards when overweight claimants made an effort to comply with prescribed activity routines. The council hopes its proposals will lead to savings across the community.